Rodletless, a new Aspergillus developmental mutant induced by directed gene inactivation

Area of Science:

• Mycology
• Fungal Genetics
• Cell Biology

Background:

• The Aspergillus nidulans CAN41 gene is activated by brlA during asexual development.
• Conidiophore cells and spores have an external rodlet layer crucial for function.

Purpose of the Study:

• To investigate the genetic basis of the rodlet layer in Aspergillus conidiophores.
• To characterize the function of the rodlet layer in spore dispersal.

Main Methods:

• Gene disruption of CAN41.
• Phenotypic analysis of mutant strains.
• Gene sequencing and protein analysis.

Main Results:

• Disruption of CAN41 resulted in a rodletless phenotype, affecting spore hydrophobicity and dispersal.
• The rodletless mutation identified a new locus, rodA, on chromosome III.
• rodA encodes a hydrophobic polypeptide with 8 cysteines, similar to proteins in Schizophyllum commune.

Conclusions:

• The rodA gene product is essential for forming the rodlet layer in Aspergillus.
• This layer is vital for efficient asexual spore dispersal.
• The 8-cysteine polypeptides represent a conserved class of fungal cell wall proteins important for aerial structures.